1. Field of the Invention
The present invention relates to a deposition mask, and more particularly, to a deposition mask used in the manufacture of a display device.
2. Description of the Related Art
Electroluminescent elements, which are self-luminous display elements, are drawing attention as next-generation display elements due to their wide viewing angle, high contrast, and high response speed.
These electroluminescent elements are divided into inorganic electroluminescent elements and organic electroluminescent elements according to the material which forms a light-emitting layer. Organic electroluminescent elements have higher luminance and response speed than inorganic electroluminescent elements, and are capable of displaying color images. Due to these advantages, organic electroluminescent elements are being actively developed.
Display devices using organic electroluminescent elements are manufactured through various deposition processes, and a deposition mask is used in part of the manufacturing process.
A deposition mask includes a mask frame and a mask sheet. A deposition mask is manufactured by tensioning and fixing a divided or undivided mask sheet onto a mask frame. For example, the mask frame and the mask sheet may be fixed to each other by welding fixing regions of the mask frame to the mask sheet. In this case, however, regions of the mask frame, other than the fixing regions, are often not completely attached to the mask sheet although they are located very close to each other. Thus, if foreign substances are introduced into the space between these regions of the mask frame and the mask sheet, a gap may be formed between the deposition mask and a substrate. The gap may hamper precise deposition of patterns and create shadows which are the cause of mask defects.